Mouse Genetics Core-Hearing loss is the most frequent sensory defect in humans. Congenital, perinatal or early onset hearing loss occurs at approximately 7 out of 1000 neonates in the United States. In approximately half of the children born with severe hearing impairment, a genetic contribution is suspected. The powerful molecular and genetic techniques available in mouse combined with the functional similarities between mouse and human audition make mouse a useful model system for studying deafness. In order to support users of mouse models for genes affecting the auditory system function, we will provide technical support in the form of expert husbandry (receiving, setting up crosses, weaning, fostering, background transfers, etc), genotyping, and notification/delivery of requested mice to the users. Per diem charges for mouse care will be the responsibility of the user, provided that they have a funded project that includes support for mouse care. In order to encourage innovative and new collaborative projects, we will provide per diem support for pilot/new studies that are not currently funded for mouse work. To monitor usage and provide equitable access, we will review, periodically, animals to be maintained by the Core. This core will provide a critical function for a variety of users. Efficiency of mouse care will be greatly increased by having centralized, expert mouse husbandry and genotyping. This will allow users not proficient in mouse care to use the vast number of identified gene knockout mice and defined spontaneous mutants to further their research. Experienced mouse users will benefit from the familiarity of the Core personnel with mouse behavior and care, allowing increased health and higher fecundity among their strains. All users will benefit by knowing about the strains, techniques, and projects being pursued by other users of the core.